Fertility Reviews is your online source for expert and professional reviews of the latest news, research, and developments in fertility treatment and IVF from a top infertility specialist in New York City.

A healthy pregnancy requires at least one healthy egg to be present in the company of at least one (but usually millions) of healthy sperm. A semen analysis is usually the screening test used to check for evidence of “male factor” infertility, i.e. some deficiency in the quantity or quality of sperm that may be contributing to a couple’s difficulty conceiving. In at least 30-40% of couples undergoing evaluation for infertility, a semen analysis will reveal some abnormality in at least one of the major categories by which we judge sperm: concentration (how many), motility (what percentage of the sperm are swimming properly), and morphology (what percentage of the sperm have a normal shape).

The task of deciding whether or not the semen analysis is “normal” may seem simple, but in reality it is often hardly clear-cut. For one thing, a man’s sperm parameters can change on a daily basis, so one borderline normal or abnormal result may not tell the whole story. For this reason, a fertility specialist will sometimes request the male partner to produce a second sample before deciding whether or not a man has a meaningful abnormality. Many specialists will recommend a 6-10 week waiting period before repeating the semen analysis. This is because the “life cycle” of a man’s sperm is approximately 60-80 days, such that two abnormal semen analyses spaced by this much time provides stronger evidence of a “true” (i.e. persistent, as opposed to transient) problem.

While severe male factor infertility is uncommon and is usually caused by an identifiable/specific medical condition (e.g. genetic, hormonal, anatomic, etc.), more mild sperm issues are quite common and often have no specific explanation. In fact, in men with more minor abnormalities, it can be unclear as to whether the semen analysis represents a real explanation for infertility at all, as the boundaries between normal and abnormal are chosen using math and statistics, but they change over time and don’t correspond specifically to any biological process or condition (the World Health Organization reference values are the ones most commonly used; they last underwent a major update in 2010).

The lack of an explanation/reason for the problem can be frustrating for couples with mild male factor infertility. Only a few lifestyle issues have been clearly shown to be important, such as smoking, marijuana use, and steroid use. A couple of recent studies have tried to find a relationship between a man’s diet and his semen analysis. In one study, a relatively weak association was found between high total dietary fat intake and low sperm concentration and motility; this relationship was driven in large part by saturated fat in particular. In another study, men consuming an overall healthier diet had very slightly better sperm motility, but no difference in concentration or morphology.

Like many studies looking at dietary issues, these studies used diet questionnaires, which are notoriously unreliable. Furthermore, the associations the studies found were slight and their true significance is questionable. While both studies suggested the possibility of an association between a healthier diet and better sperm counts, the role of diet and nutrition in male factor infertility is far from certain and needs further, and more rigorous, investigation.

Most women who have undergone an infertility workup, and almost all women who have gone through infertility treatment, have probably been tested for their progesterone level at some point in the process. A recent statement published by the American Society for Reproductive Medicine (ASRM) provides a good opportunity to revisit what we know (and what we don’t) about the role of progesterone in infertility treatment.

Broadly speaking, progesterone is the hormone that supports pregnancy. Discovered in the 1930’s at the University of Rochester, pro-gest-er-one was named for its role as the “pro-gestational (i.e. supporting gestation, or pregnancy) steroidal ketone.” During a natural menstrual cycle, as part of the highly synchronized natural interplay between the ovaries and the uterus that occurs each month in order to facilitate the possibility of pregnancy, progesterone is produced starting just after ovulation; the source of the progesterone, conveniently enough, is actually the very follicle left behind by the egg that has been ovulated. This structure, called the “corpus luteum,” can usually be seen on transvaginal ultrasound within a couple of days after ovulation. The main job of the progesterone at this point is to transform the cells in the uterine lining (aka endometrium) into a surface that will be receptive to the implantation of a fertilized egg (aka embryo).

The corpus luteum typically continues to produce progesterone for about 12-14 days; at that point, if no embryo has implanted, the corpus luteum disintegrates, and the resulting drop in progesterone causes a menstrual bleed. If, however, the egg that was ovulated is fertilized and the resulting embryo implants in the lining of the uterus, the embryo itself produces the hormone hCG (human chorionic gonadotropin) and “rescues” the corpus luteum, allowing it to continue producing progesterone. Progesterone, in turn, supports the continued growth of the pregnancy. Quite poetically therefore, it turns out that the pregnancy needs progesterone as much as the source of the progesterone (the corpus luteum) needs the pregnancy (for hCG). If the progesterone production is somehow interrupted -- for example, if the ovary containing the corpus luteum is surgically disturbed or removed during this period of time (up to about 8 weeks gestation, at which the point the placenta takes over progesterone production), the pregnancy will most likely fail, resulting in miscarriage.

Given the critical role that progesterone plays in “supporting” pregnancy, it has long been speculated that progesterone deficiency, referred to as “luteal phase deficiency (LPD),” might be an important cause of infertility in couples who have no other obvious issue. As the recent ASRM statement confirms, however, whether or not LPD is a real cause of infertility in otherwise healthy women is doubtful at best. Furthermore, even if we assume LPD is real, there is little convincing evidence that treating LPD (typically with supplemental progesterone) will improve the situation. An important exception to this statement is in IVF/ART cycles (as opposed to non-medicated cycles or IUI cycles), when luteal function is clearly interrupted, and supplementing progesterone has been shown to be important. (Tangentially, new data actually questions whether we need to continue the progesterone supplementation as long as we do)

ASRM summarizes our current knowledge about LPD as follows:

Abnormal luteal function may occur as the result of a medical condition (e.g., elevated prolactin, abnormal thyroid function), and infertile women should be investigated for these disorders with appropriate treatment of identified conditions.

No diagnostic test for luteal phase insufficiency has been proven reliable in a clinical setting. The roles of basal body temperature, luteal progesterone levels, endometrial biopsy, and other diagnostic studies have not been established, and performance of these tests cannot be recommended.

No treatment for luteal phase insufficiency has been shown to improve pregnancy outcomes in natural, unstimulated cycles.

Luteal support after ART procedures with progesterone or hCG improves pregnancy outcomes, but hCG increases the risk of OHSS.

There is no proven role in adding progesterone or hCG for luteal support once a pregnancy has been established. Use of supplemental progesterone, in a non-ART cycle beyond the time of expected menses (i.e., 2 weeks after ovulation), is not proven beneficial.

Fertility medicine is quite remarkable for its almost obsessive focus on quantitative outcomes. This is probably partly due to the binary nature of what we do (pregnant vs. not pregnant, baby vs. no baby, etc.) and partly to the elective (and therefore competitive) nature of the “fertility business,” a trend that was undoubtedly intensified by the 1992 federal law requiring all IVF clinics to report their outcomes to the CDC.

While “pregnancy rate” (percent of women getting pregnant per IVF attempt) has historically been the mainstay of how outcomes are reported, many fertility specialists advocate alternate measures of success. One approach emphasizes the importance of a baby (“live birth”) over a mere pregnancy (with the difference being miscarriages and stillbirths). In a different vein, others have advocated adjusting the time frame from “per cycle” success to “cumulative” success, arguing that what is really most important to a patient is what the chances are that at the conclusion of a course of treatment, she will achieve success. This last point is particularly germane in an infertile population, as there is usually some degree of “natural selection” that occurs over the course of multiple treatment attempts: the “least infertile” couples (i.e. those with the most mild problems) tend to get pregnant sooner, leaving behind an increasingly infertile group to try again the next time. Statistically, this often leads to worse outcomes in subsequent treatment cycles (one can think of this as “diminishing returns” on the treatment investment after multiple failed attempts).

Two large studies using newer measures of treatment success have been published recently (links below). The first, published in the New England Journal of Medicine, analyzed cumulative live birth data from the national (U.S.) database compiled by the Society for Assisted Reproductive Technology. The authors “linked” data belonging to individual women who underwent multiple IVF cycles and calculated cumulative success rates after multiple attempts. They found several trends:

a) Amongst women using their own eggs, cumulative success increases dramatically in the first 3 attempts and increases more slowly during IVF attempts #4-6 (very few women pursued 7 or more cycles)

b) Whereas age is a big factor in cumulative success amongst women using their own eggs (i.e. younger women have more success), “older” women using donor eggs do not have significantly decreased cumulative success despite their age, as compared with younger women using donor eggs

c) Blastocyst (day 5 or 6) embryo transfers are associated with higher cumulative success than cleavage stage (day 2 or 3) embryo transfer (Although this may not be a true cause-and-effect relationship, since the women having blastocyst transfers tend to be younger and/or have more available embryos from which to choose)

The second study, published in Fertility and Sterility, looked specifically at cumulative success in egg donation cycles, and used a new measure they termed “cumulative newborn rate per number of embryos transferred” – a rate using number of newborns (as opposed to pregnancy) as the numerator and number of embryos transferred -- instead of number of treatment cycles performed -- as the denominator. This outcome measure will thus take into account the efficiency of the treatment, recognizing that transferring 3 embryos in one cycle is not the same as transferring one embryo in one cycle.

This group of researchers showed that most of the babies (65%) are achieved with the first 5 embryos transferred, 85% with the first 15 embryos, and cumulative success ultimately levels off between 90-95% after 16-25 embryos have been transferred. Interestingly, and in accordance with many previous studies (such as the one mentioned above), neither the age of the recipient nor the diagnosis (i.e. reason for pursuing oocyte donation) had any significant influence on cumulative outcomes.

While every IVF clinic does things a bit differently, there is broad consensus that the two core components of “monitoring” response to medication during an IVF cycle include:

Blood estradiol

Follicle growth as measured by transvaginal ultrasound

That said, there are multiple reasonable approaches to IVF; some clinics also like to check other hormones, such as FSH, LH, and progesterone at certain times during the IVF stimulation.

Three recent studies (links below) highlight growing evidence supporting the importance of checking progesterone during an IVF cycle, particularly in the latter part of the cycle (after 6 or 7 days of medication). Progesterone is the hormone that causes the uterine lining to become receptive to pregnancy (“pro-” i.e. supporting, “gest” i.e. gestation/pregnancy). In normal physiology, progesterone is produced mainly by the corpus luteum, the structure resulting from the follicle after the egg has been released. By definition, therefore, progesterone action is timed by nature to kick in after ovulation, when a conceptus may be looking for a place to implant.

In an IVF cycle, however, due to the growth of multiple follicles (rather than just one, as nature would have it), progesterone levels sometimes start to rise prematurely – before ovulation, and even before the oocyte retrieval is performed. Early exposure to elevated progesterone levels is theorized by some to have detrimental effects on an embryo’s ability to implant. In other words, even the slight increase in progesterone levels caused by the IVF stimulation may throw off the synchronicity of the embryo and the lining enough to decrease chances of pregnancy.

There have been multiple studies aiming to address this subject in the past 10-20 years, and the results have been inconsistent. Many of these have been small studies using different cutoffs for what is considered an “elevated” progesterone level. Two of the studies cited below are amongst the largest ones that demonstrate a link between elevated progesterone and decreased chances of IVF success. The third, and perhaps most intriguing, takes this idea of “progesterone timing” even further and looks at the duration of progesterone elevation in addition to the amount. Taken together, I believe these studies warrant serious consideration when there is evidence of a premature progesterone rise prior to egg retrieval in an IVF cycle. While no studies address the question of what is the best plan of action in this situation, one logical option would be to forgo a fresh embryo transfer in order to allow the lining to “recover,” and plan for a frozen-thaw cycle with a healthy, well-timed lining 1-2 months later.